vdex optimization: avoid doing application type resolution.

When looking up for methods/fields, we can take the class
that was originally found as holding the method. If a subclass
of that class ends up redefining it after an OTA, it cannot
alter the expected flags anyways (eg a public method cannot be
overridden with a non-public method).

bug: 30937355
test: test-art-host
Change-Id: Ie3fbe0e829a27db61c534c4a49e945cc1afed9b9